Back to the rootsComputer Scientists of the University of Paderborn are researching on self-stabilization of overlay-networks

Paderborn. Professor Dr. Christian Scheideler of the Institute of Computer Science at the University of Paderborn develops self-stabilizing algorithms for overlay networks. In line with a research project of the DFG he is conjointly working with the degreed computer scientists Sebastian Kniesburges and Andreas Koutsopoulos until the end of July 2011. They try to get overlay-networks to transform themselves back to their primal state so that they are more robust against a highly changing amount of members and hostile attacks.

In present-days individual computers are increasingly networking with others. Peer-to-peer Systems, platforms and social networks emerge which enable a fast exchange of data and information. Across the internet, in a manner of speaking, “over” the internet, the so called overlay-networks are generated, so that the exchange of data can be performed in a highly efficient way.

As peer-to-peer systems are easily vulnerable and perpetually regenerating themselves, as the connection of the individual peers to the internet is not constantly given, distributed self-stabilizing methods have to be developed to enable an overlay-network to regain its primal topology out of every condition. “Ideally this should come to pass through the use of sheer local interactions between the individual knots”, says Christian Scheideler.

If one assumes that the individual peers are tagged with unambiguous numbers and that the connections accumulate to a sorted list in the end, it would indeed be possible that every peer just adheres to connections to the (one or two) peers with the next number to his own number and all the other connections are delegated to more suitable peers. „This is how the sorted list is slowly coming into existence“, explains Scheideler. “The sorted list is indeed the only stable topology for this rule”, he adds.

Up to now the professor and his team discovered in several operations that the different categories of networks are effectively able to repair themselves. The group of research is currently writing down a method which is applicable to a broad category of topologies.

In order to reveal the complex of problems concerning the overlay-networks to the students, too, student assistants are currently designing a platform named PALATIN, which renders the possibility to test overlay-networks in reality. “It is awesome that I have this platform as a tool which enables me to also deal with the results in lectures, too”, Scheideler gladly announces. He is contented that the students of computer science are also going to have the chance to comprehend the work of the project.